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151.
Confined chorionic mosaicism in prenatal diagnosis 总被引:4,自引:1,他引:3
Dagmar K. Kalousek Fred J. Dill Tapio Pantzar Barbara C. McGillivray Siu Li Yong R. Douglas Wilson 《Human genetics》1987,77(2):163-167
Summary Confined chorionic mosaicism, detected commonly on chorionic villus sampling (CVS) and occasionally in cultured amniotic fluid cells, is described in five pregnancies that showed confined chorionic mosaicism for trisomies 12, 13, 14, 17 and a marker chromosome. Cytogenetic findings in these pregnancies support the conclusion that within chorion some chromosomal mosaicism are confined to the trophectoderm derivatives while others to the extra-embryonic mesoderm. The etiology of confined chorionic mosaicism is discussed in relation to a significant role of multiple cell lineages contributing to the early development of placenta. The need is indicated for the use of both direct and long-term cultures in CVS prenatal diagnosis, and for the confirmatory testing of fetal blood or amniotic fluid in cases where mosaicism is detected in chorionic villi. 相似文献
152.
153.
The effects of PGF2α infusion in a dose of 25 μg/min for 5 hours on serum levels of estradiol-17β, progesterone, LH, FSH, TSH and prolactin, and on the pituitary hormone responsiveness to LRH and TRH were studied in 10 apparently healthy cycling women in the mid-luteal phase. No systematic alteration was seen in the pituitary and ovarian hormone levels during PGF2α infusion, and the pituitary hormone responses to releasing hormones were unaffected. Ovarian steroid production increased in response to increased gonadotropin levels after LRH injection during PGF2α administration. These results confirm that PGF2α is not luteolytic in humans and no apparent relationship between PGF2α and pituitary hormone secretion exists. 相似文献
154.
Tapio?PahikkalaEmail author Filip?Ginter Jorma?Boberg Jouni?J?rvinen Tapio?Salakoski 《BMC bioinformatics》2005,6(1):157
Background
The ability to distinguish between genes and proteins is essential for understanding biological text. Support Vector Machines (SVMs) have been proven to be very efficient in general data mining tasks. We explore their capability for the gene versus protein name disambiguation task. 相似文献155.
Tapio S Danescu-Mayer J Asmuss M Posch A Gomolka M Hornhardt S 《Mutation research》2005,581(1-2):141-152
Arsenic present in drinking water and mining environments in some areas has been associated with an increased rate of skin and internal cancers. Contrary to the epidemiological evidence in humans, arsenic does not induce cancer in animal models, but is able to enhance the mutagenicity of other agents. In order to achieve a better understanding of the interaction between arsenic and ionising radiation, an investigation was conducted to detect differences at the proteome level of human TK6 lymphoblastoid cells exposed to these agents. Cells were exposed to either a single dose of 1-Gy 137Cs-gamma-rays or to 1 microM arsenite (As(III)) or to both agents in combination. Two-dimensional (2D) electrophoresis and matrix-assisted laser desorption/ionisation-time of flight (MALDI-TOF) were employed for the screening and identification of proteins, respectively. It proved possible to identify seven proteins with significantly affected abundance, three of which showed increased levels and the remaining four showed decreased levels under at least one of the exposure conditions. Following arsenite treatment or irradiation, a significant increase compared with that of the control was observed for glutathione (GSH) transferase omega 1 and proteasome subunit beta type 4 precursor. The combined exposure did not result in an induction of the enzymes. The expression of electron-transfer flavoprotein subunit alpha was found to be enhanced under all three-exposure conditions. Ubiquinol-cytochrome C reductase complex core protein I, adenine phosphoribosyl transferase and endoplasmic reticulum protein hERp29 showed decreased levels after irradiation or arsenite treatment, but not after the combined exposure. The level of serine/threonine protein phosphatase 1 alpha decreased with all treatments. The main conclusions are that both arsenite and gamma-radiation influence the levels of several proteins involved in major metabolic and regulatory pathways, either directly or by triggering the defence mechanisms of the cell. The combined effect of both exposures on the level of some essential proteins such as glutathione transferase, proteasome or serine/threonine phosphatase may contribute to the co-carcinogenic effect of arsenic. 相似文献
156.
157.
Puurtinen M Knott KE Suonpää S van Ooik T Kaitala V 《Evolution; international journal of organic evolution》2004,58(4):749-756
Abstract Population genetic theory predicts that in small populations, random genetic drift will fix and accumulate slightly deleterious mutations, resulting in reduced reproductive output. This genetic load due to random drift (i.e., drift load) can increase the extinction risk of small populations. We studied the relationship between genetic variability (indicator of past population size) and reproductive output in eight isolated, natural populations of the hermaphroditic snail Lymnaea stagnalis . In a common laboratory environment, snails from populations with the lowest genetic variability mature slower and have lower fecundity than snails from genetically more variable populations. This result suggests that past small population size has resulted in increased drift load, as predicted. The relationship between genetic variability and reproductive output is independent of the amount of nonrandom mating within populations. However, reproductive output and the current density of snails in the populations were not correlated. Instead, data from the natural populations suggest that trematode parasites may determine, at least in part, population densities of the snails. 相似文献
158.
Chunyang?LiEmail author Olavi?Junttila E.?Tapio?Palva 《Acta Physiologiae Plantarum》2004,26(2):213-222
Cold acclimation of plants is a complex process involving a number of biochemical and physiological changes. The ability to
cold acclimate is under genetic control. The development of freezing tolerance in woody plants is generally triggered by non-freezing
low temperatures but can also be induced by mild drought or exogenous abscisic acid, as well as by short photoperiod. In nature,
the extreme freezing tolerance of woody plants is achieved during sequential stages of cold acclimation the first of which
is initiated by short photoperiods and non-freezing low temperatures, and the second by freezing temperatures. Although recent
breakthroughs have increased our knowledge on the physiological molecular basis of freezing tolerance in herbaceous species,
which acclimate primarily in response to non-freezing low temperatures, very little is known about cold acclimation of woody
plants. This article attempts to review our current understanding of the physiological aspects that underline cold acclimation
in woody plants. 相似文献
159.
Kiviniemi AM Hautala AJ Seppänen T Mäkikallio TH Huikuri HV Tulppo MP 《American journal of physiology. Heart and circulatory physiology》2004,287(5):H1921-H1927
This study was designed to assess the relationship between R-R interval length and heart rate (HR) variability in healthy subjects and patients after an acute myocardial infarction (AMI). Twenty-four-hour ambulatory ECG recordings were obtained for 76 healthy subjects and 82 post-AMI patients. The high-frequency (HF, 0.15-0.4 Hz) spectral power of R-R intervals was analyzed in 5-min sequences over 24 h and plotted as a function of the corresponding mean R-R interval length. Quadratic regression model was used to study the relationship between R-R interval length and HF power. If a distinct deflection point (R-R0) occurred in the quadratic regression (r >0.50) model before maximum R-R interval, indicating the plateau of HF power, the relationship between R-R interval and HF power was defined as saturated. Otherwise, the relationship was defined as linear (r >0.50) or low correlated (r >0.50). The relationship was saturated in 35, linear in 38, and low correlated in 3 healthy subjects. In post-AMI patients, the relationship was saturated in 9 subjects, linear in 44 subjects, and low correlated in 29 patients. The HF power analyzed from the 24-h period did not differ between the saturated and linear groups, but when analyzed from the linear portion only, HF spectral power was smaller in the linear than the saturated group both among healthy subjects (P <0.05) and post-AMI patients (P <0.05). Saturation of the HF oscillations of R-R intervals is a common phenomenon in healthy subjects and also present in post-AMI patients during ambulatory conditions. This saturation effect may bias the quantification of cardiac vagal function when HR variability is analyzed from Holter recordings. 相似文献
160.
Tiimonen H Aronen T Laakso T Saranpää P Chiang V Ylioja T Roininen H Häggman H 《Planta》2005,222(4):699-708
Transgenic silver birch (Betula pendula Roth) lines were produced in order to modify lignin biosynthesis. These lines carry COMT (caffeate/5-hydroxyferulate O-methyltransferase) gene from Populus tremuloides driven by constitutive promoter 35S CaMV (cauliflower mosaic virus) or UbB1 (ubiquitin promoter from sunflower). The decreased
syringyl/guaiacyl (S/G) ratio was found in stem and leaf lignin of 35S CaMV-PtCOMT transgenic silver birch lines when compared
to non-transformed control or UbB1–PtCOMT lines. In controlled feeding experiments the leaves of transgenic birch lines as
well as controls were fed to insect herbivores common in boreal environment, i.e., larvae of Aethalura punctulata, Cleora cinctaria and Trichopteryx carpinata (Lepidoptera: Geometridae) as well as the adults of birch leaf-feeding beetles Agelastica alni (Coleoptera: Chrysomelidae) and Phyllobius spp. (Coleoptera: Curculionidae). The feeding preferences of these herbivores differed in some cases among the tested birch
lines, but these differences could not be directly associated to lignin modification. They could as well be explained by other
characteristics of leaves, either natural or caused by transgene site effects. Growth performance of lepidopteran larvae fed
on transgenic or control leaves did not differ significantly. 相似文献